On interfaces, paper tape readers/punches,

[Tony Duell]

> 
> As said before, one can easily get some of the small (8 pin dip) micros to do
> magic things, but sometimes (as mentioned) it is a bit more trouble than it is
> worth.  Many of us (me!) have stuff in their junk
> boxes^H^H^H^H^H^H^H^H^H^Hclassic part archive that will do the task quite
> easily.  In my case, I obtained a nice Facit 4070 paper tape punch and made up
> a simple interface adapter (it fit inside one of those 2x DB-25 scramble boxes)
> to make it function using a PeeCee parallel port.  Now if I desire to punch a
> paper tape, all I do is a simple copy to the printer port and ...buzzzz... out
> comes the tape.  Thankfully the Facit 4070 had some power available on its

Somewhat surpisingly, when I wanted to do this, I just wrote a bit of 
software to drive the PC port lines appropriately. It wasn't that 
difficult :-)

> DB-25, but I needed to play around with all the levels (it used 6 volt levels).
>  In the end, all it took was a single 74LS00 to do the trick on changing the
> strobes to conform.

I seem to rememebr that when I did it that way, I used a '74 D-type and a 
quad gate package (I forget which).

A word of warning to anyone working on a 4070. The interface may not be 
what you expect!. The 4070 has 2 edge connectors and PCBs in the bototm 
of the unit. The top board, in evey case that I've seen, is the standard 
Facit control logic/PSU, and has the interface you've been usign The 
lower edge connector intercepts the interface signals between this board 
and the DB25 on the back of the unit. Im _many_ cases there's a simple 
jumper board in that slot, so you get the 'Facit parallel' interface on 
the D25. But they certainly made a serial interface (RS232 and current 
loop) to go there -- I have one. An IEEE-488 interface has been rumoured, 
but I've not seen that. And HP badged this punch but put their own 
interface i nthat slot, it inverts some of the signals, etc.

-tony